Process of manufacturing copper sulfate.



No. 679,985. Patented Aug. 6, I90I. H. PALAS &. F. GOTTA.

PROCESS 0F MANUFACTURING GPPER SULFATE.

(Application led July 1.1, 1899.) (No Model.)

WITNE ssfs /NVfNTORS HIPPOLYTE PHL/i5 Qff? 1Q THEIR HTRNEYS.

wzqnm Parras co.. lm-ummm msumcrron. u4 cy UNITED' STATES PATENT OFFICE.

HIPPOLYTE PALAS AND FLIX COTTA, 0F MARSEILLES, FRANCE.

PROCESS OF MANUFACTURING COPPER SULFATE.

SPECIFICATION forming part `of Letters Patent No. 679,985, dated August 6, 1901.

Application filed July 11, 1899. serial No. 723,502. (No specimens To a/ZZ whom, it nung/'concern- Beit known that we, HIPPOLYTE PALAs and FLIX GOTTA, chemists, of 118 Grand Chemin de Toulon, Marseilles, France,'have invented a certain new and useful Process of Manufacturing Copper Sulfate or other Metallic Sulfates, of which the following a specification.

This invention relates to a process for manufacturing copper sulfate or other metallic sulfates by the application of electrolysis to a solution of sodium sulfate or potassium sulfate.

This process enables crystals of metallic sulfate prepared in an absolutely-pure state to be obtained and avoids all loss of sulfuric acid, as takes place in the ordinary preparation of copper sulfate by the action of sulfuric acid on waste copper. In this operation a strong proportion of sulfuric acid disappears in the state of sulfurous acid- Our process insures, in addition to the preparation of sulfate, the production of the base, sodium or potassium, of the electrolyzed alkaline sulfate.

For the purpose of carrying our process into eect We employ an electrolyzing appatus such as that hereinafter described; but for greater simplicity we shall first consider an elementary electrolytic apparatus comprising two compartments separated by a diaphragm. In one of these compartments We place a solution of alkaline sulfate of a strength of about 25 Baume and which is heated to a temperature of about 70 centigrade, so as to diminish as much as possible the electrical resistance. Within this compartment is arranged a plate or strip of iron or other metal which will not be acted upon by the sodium and which forms the cathode. In the other compartment is located a plate forming the anode and which consists of the metal which is to be transformedfor example, copper. If it is wished to manufacture copper sulfate, this compartment is filled with a solution p of sulfate of this metal, which is intended to prime the reaction. This solution ought to have a density and a temperature corresponding with the greatest electrical conductivity. If there be set up between the two electrodes a dierence in potential of 2.5 to 3 volts, according to the resistance of the bath, the sulfate of sodium (or of potassium) separates into sodium (or potassium) and sulfuric acid in the form of S04. The sodium (or potassium) remains in the compartment of the cathode and the ion S04 passes from this compartment into that of the anode across or through the diaphragm. 0n 'the other hand, the copper sulfate contained in the compartment of the anode is electrolyzed in the following manner: The copper Cu, meeting through the diaphragm the ion S04, immediately re-forms sulfate of copper. As for the ion S04 from the decomposed copper sulfate it at once acts upon the copper anode in contact with which it is evolved,and thus forms copper sulfate,which enriches the solution. Here takes place a phenomenon which diminishes in notable proportions the quantity of energy necessary to decompose the alkaline sulfate. The action upon the anode by S04 gives rise to an electrical current of the same direction as the principal electrolytic current and which is added there to. It thus increases the quantity of electrochemical work, which is equivalent to an economy of current. There is finally in the cathode-compartment amixture of caustic soda (or potash) and alkali-metal sulfate. This latter can be easily separated by crystallization of the evaporated lixivium of soda, (or potash.) With regard to the anode-compartment, it contains a solution of copper sulfate mixed with a small quantity of alkaline sulfate, which furnishes at the time of crystallization extremely-pure crystals of copper sulfate.

We have for greatersimplicity supposed up to this point that the operation has been performed in an electrolytic apparatus of which the positive and negative compartments are separated by any ordinary commercial diaphragm; but in our practice it would not actually be so, because if a solution of an alkaline sulfate be electrolyzed in an electrolytic apparatus containinga soluble anode the alkali and metallic sulfate produced will meet within the thickness or substance of the diaphragm, and there are formed certain oxids which close the pores and impede or soon prevent the passage of the current. That is a primordial inconvenience in- IOO ' of the electrolyzer.

herent in all electrolytic apparatus hitherto employed. We have been able to remedy this, and to consequently render our process eminently a commercial one, by contriving duced by employing a hollow porous plate orV diaphragm and by causing the solution of the alkaline sulfate which is to be electrolyzed to arrive actually within this plate and by forcing the solution to filter 'through the walls of this diaphragm, which divides it into two opposite currents directed the one toward the cathode-compartment and the other toward that of the anode. In this manner both the alkali and the metallic sulfate produced are at each moment removed or separated from the central portion of the diaphragm. This diaphragm is composed of two sheets or layers a b of asbestos or other suitable material which is both porous and a good filtering medium, these sheets being brought close together and forming a closed pocket having vertical walls. The solution of alkaline sulfate reaches this pocket from a pipe `c-for example, under pressure-penetrating into and filtering through the compartments of the cathodes d and those of the anodes e In these compartments it undergoes electrolytic decomposition and passes out in a constant manner by the pipes opening at ff. By this double movement of the liquid the metallic sulfate produced o'n the anode side cannot come into contact with the alkali produced at the cathode.

In practice the apparatus is formed by the juxtaposition of rectangular frames g, having only three sides and strongly clamped or otherwise secured one against another in the manner of a filter-press. The ends are closed by plates h in such a manner that the apparatus presents the appearance of a rectangular trough or vat and one which can easily be taken to pieces and is perfectly watertight. eled metal, or of other suitable material. Between two consecutive frames are placed the asbestos sheets a and b, forming the closed pocket wherein the solution of alkaline s111- fate arrives under pressure. The vertical walls of these pockets form, with the frames, the various compartments of the apparatus. These contain alternately the anodes e and the cathodes d. Lastly, the Walls of thepockets aremaintained smooth by Wooden or glass grids t. The alkali and metallic sulfate produced can escape by pipes j la. Each compartment being only a few centimeters wide, averaging three or four centimeters, the electrodes are very close together, and conse- These frames may be of wood, enamquently the electrical resistance of the apparatus is very small.

Our process thus allows the manufacture of metallic sulfates, and in particular copper sulfate, by borrowing sulfuric acid directly from the sodium (or potassium) sulfate without loss of sulfurous acid and with but a small expenditure of energy. This sulfuric acid is transformed immediately and in the electrolyzing apparatus itself proportionally or according to its formation.

The .caustic alkali obtained as a subproduct and whose selling price is fairly high diminishes in very large proportions the net cost of the sulfates, and particularly of copper sulfate. Y

We wish to observe that the copper anode A may be formed either of a plate-or strip of this metal or of waste or chips or ores of any form whatever. The said anode might thus be composed of the residues from the roasting of copper pyrites. We should in that case extract the copper directly from these residues in the state of sulfate.

What we claim as our invention, and desire 4to secure by Letters Patent, is Y l. A process of producing metallic sulfates and simultaneously obtaining an alkaline base as a by-product by electrolysis, said process consisting in separating the anode and cathode by a porous diaphragm, supplying a stream of the electrolyte solution of an alkalimetal sulfate to a soluble anode of the metal to be transformed into sulfate, supplying another stream of the same electrolyte solution to the cathode on Vthe other side of the diaphragm and passing a current of electricity therethrough, all substantially as described.

2. A process of producing copper sulfate and simultaneously obtaining an alkaline base as a by-product by electrolysis, said process consisting in separating the copper anode from the cathode by a porous diaphragm, sup plying a stream of an alkali-metal sulfate to the copper anodeA and. supplying another stream of the same electrolyte solution to the cathode on the other side of said diaphragm and passing a current of electricity therethrough all substantially as described.

3. A process of producing copper sulfate and simultaneously obtaining an alkaline baseas a by-product by electrolysis, said process consisting in separating the copper anode from the cathode by a hollow porous diaphragm, feeding a stream of an alkali-metal sulfate into the hollow diaphragm, whence two streams of the same electrolyte solution are supplied one to the anode and the other to the cathode, and passing a current of electricity therethrough, substantially as dee. scribed.

4, A process of producing metallic sulfatos and simultaneously obtaining an alkaline base as a by-product,by electrolysis,said process consisting in separating the anode and cathode solutions by a porous diaphragm, supplying a stream' of the electrolyte solution of IOO IIO

Igd

i l fl l l i an alkali-metal sulfate to a soluble anode of the metal to be transformed into sulfate, supplying another stream of the same electrolyte to the cathode 0n the other side of the diaphragm, and passing a current of electricity therethrough and drawing o the electrolyzed solution as the process goesV on, all substantially as described.

5. A process of producing copper sulfate and simultaneously obtaining an alkaline base as a byproduct,by electrolysis,said process consisting in supplying a stream of the electrolyte solution of an alkali-metal sulfate to a copper anode on one side of a porous dia- 

